Devices and Methods for Correcting Vertebral Misalignment

ABSTRACT

Embodiments of devices and methods of correcting vertebral misalignment, including, e.g., spondylolisthesis, are disclosed. In one embodiment, a vertebral implant may include an assembly configured to be secured to a first vertebral body, wherein the assembly includes a frame made of a first material and at least one end plate made of a second material different than the first material; a reducing plate configured to be slidably received over the central portion, wherein the reducing plate is configured to be secured to a second vertebral body; and an actuator configured to move the reducing plate relative to the frame.

FIELD OF THE INVENTION

Embodiments of the present disclosure relate generally to correctingmisalignment of vertebral bodies comprising the spinal column. Moreparticularly, embodiments of the present disclosure relate tostabilizing dislocated vertebral bodies to, among other things, correctspondylolisthesis and other spinal column injuries or deformities.

BACKGROUND

Spondylolisthesis is a medical condition in which one vertebral bodyslips (e.g., anteriorly) in relation to an adjacent vertebral body,usually in the lumbar region of the spine. This condition can causesymptoms that include pain in the lower back, thighs, and/or legs,muscle spasms, weakness, and/or tight hamstring muscles. In some cases,however, the presence of spondylolisthesis can be identified only byradiographic imaging (e.g., X-ray).

One solution for correcting spondylolisthesis and other similarconditions of vertebral dislocation may include reconstructive surgeryand fusion of the affected vertebral body to an adjacent vertebral body.Vertebral fusion is generally accomplished by removing the native discand then fixing an apparatus to and between the misaligned vertebrae. Inaddition to the stabilization and correction of spondylolisthesis,embodiments of the present disclosure may facilitate correction ortreatment of other spinal conditions, including, but not limited to,stabilization of fractures, correction of spinal deformities (e.g.scoliosis and/or kyphosis), stabilization and correction of degenerativespinal lesions and narrow spinal canal, reconstruction after tumorresection, and secondary spinal surgery.

SUMMARY OF THE INVENTION

Embodiments of the present disclosure relate to, among other things,correction of spondylolisthesis by movement of the vertebrae into betteralignment while maintaining stabilization of the vertebrae in the newposition. Further, embodiments of the present disclosure may be used tomove one or more dislocated (e.g., slipped) vertebral bodies into apost-surgical position and keep the vertebrae in the post-surgicalposition during, e.g., ossification. Each of the embodiments disclosedherein may include one or more of the features described in connectionwith any of the other disclosed embodiments.

In one embodiment, a vertebral implant may include an assemblyconfigured to be secured to a first vertebral body, wherein the assemblyincludes a frame made of a first material and at least one end platemade of a second material different than the first material; a reducingplate configured to be slidably received over the central portion,wherein the reducing plate is configured to be secured to a secondvertebral body; and an actuator configured to move the reducing platerelative to the frame.

In another embodiment, a vertebral implant may include a frame assemblyinclude a left lateral portion, a central portion, and a right lateralportion, wherein the left and right lateral portions define enlargedheads configured to receive fasteners therein for securing the frameassembly to a first vertebral body, and wherein the central portiondefines a lumen therethrough; a reducing member configured to beslidably received over the central portion, wherein the reducing memberincludes an anterior portion and a plurality of plates extendingposteriorly therefrom, wherein the plurality of plates define a channeltherebetween, wherein the channel is configured to receive a portion ofthe central portion; and an actuator configured to control a position ofthe reducing member relative to the frame assembly.

In a further embodiment, a method of correcting vertebral misalignmentmay include positioning an implant within a space between two adjacentvertebral bodies, wherein the implant may include a frame assemblyinclude a left lateral portion, a central portion, and a right lateralportion, wherein the left and right lateral portions define enlargedheads configured to receive fasteners therein for securing the frameassembly to a first vertebral body, and wherein the central portiondefines a lumen therethrough; a reducing member configured to beslidably received over the central portion, wherein the reducing memberincludes an anterior portion and a plurality of plates extendingposteriorly therefrom, wherein the plurality of plates define a channeltherebetween, wherein the channel is configured to receive a portion ofthe central portion; and an actuator configured to control a position ofthe reducing member relative to the frame assembly. The method mayfurther include securing the frame assembly to a first vertebral body ofthe two adjacent vertebral bodies; securing the reducing member to asecond vertebral body of the two adjacent vertebral bodies, wherein thesecond vertebral body is disposed superiorly of the first vertebralbody; rotating the actuator to move the second vertebral body relativeto the first vertebral body; and securing the reducing member relativeto the frame assembly.

In yet another embodiment, a method of correcting vertebral misalignmentmay include accessing adjacent vertebral bodies via an anterior-onlyapproach; removing a native disc from in between the adjacent vertebralbodies to form an interbody disc space; roughening one or more surfacesof one or both of the adjacent vertebral bodies; positioning animplantable assembly within the interbody disc space. The implantableassembly may include a frame member having a substantially cylindricalcentral portion, wherein the frame member is configured to be secured toa first vertebral body of the adjacent vertebral bodies by a firstfastener; a reducing member movably secured to the frame member, whereinthe reducing member is configured to be slidably received over thecylindrical central portion, and wherein the reducing member isconfigured to be secured to a second vertebral body of the adjacentvertebral bodies by a second fastener; and an actuator for controlling aposition of the reducing member relative to the frame member. The methodmay also include adjusting a position of one of the adjacent vertebralbodies relative to the other of the adjacent vertebral bodies.

In a further embodiment, a vertebral implant may include a head portionincluding a first counterbore, a second counterbore, a thirdcounterbore, and a fourth counterbore; a plurality of planarlongitudinal members extending away from the head portion, wherein theplurality of planar longitudinal members are spaced from one another todefine a channel therebetween; and a plurality of endplates configuredto be disposed on each of the plurality of planar longitudinal members.

It may be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of thepresent disclosure and together with the description, serve to explainthe principles of the disclosure.

FIG. 1A depicts an isometric view of an apparatus for correctingvertebral misalignment in a first configuration, in accordance with anembodiment of the present disclosure;

FIG. 1B depicts a top view of the apparatus of FIG. 1A;

FIG. 1C depicts a side view of the apparatus of FIG. 1A;

FIG. 1D depicts a bottom view of the apparatus of FIG. 1A;

FIG. 2A depicts an isometric view of the apparatus of FIG. 1A in asecond configuration, in accordance with an embodiment of the presentdisclosure;

FIG. 2B depicts a top view of the apparatus of FIG. 2A;

FIG. 3A depicts the apparatus of FIG. 1A implanted between two vertebralbodies, in accordance with an embodiment of the present disclosure;

FIG. 3B depicts the apparatus of FIG. 1A adjusted to be in the secondconfiguration of FIG. 2A, in accordance with an embodiment of thepresent disclosure;

FIG. 4A depicts an apparatus for correcting misalignment of adjacentvertebral bodies, in accordance with a further embodiment of the presentdisclosure;

FIG. 4B depicts an apparatus for correcting misalignment of adjacentvertebral bodies, in accordance with another embodiment of the presentdisclosure;

FIG. 4C depicts an apparatus for correcting misalignment of adjacentvertebral bodies, in accordance with yet another embodiment of thepresent disclosure;

FIG. 4D depicts an apparatus for correcting misalignment of adjacentvertebral bodies, in accordance with a further embodiment of the presentdisclosure;

FIG. 4E depicts an apparatus for correcting misalignment of adjacentvertebral bodies, in accordance with another embodiment of the presentdisclosure;

FIG. 4F depicts an apparatus for correcting misalignment of adjacentvertebral bodies, in accordance with yet another embodiment of thepresent disclosure;

FIGS. 5A-5B depict an embodiment of using an apparatus of the presentdisclosure to re-position dislocated vertebral bodies;

FIG. 6A depicts an apparatus for correcting vertebral misalignment, inaccordance with an embodiment of the present disclosure;

FIG. 6B depicts an exploded view of the apparatus of the FIG. 6A;

FIG. 6C depicts a partially assembled view of the subcomponents of theapparatus of FIG. 6A; and

FIGS. 7A-7B depict sagittal cross-sectional views of the apparatus ofFIG. 6A in expanded and contracted configurations, respectively.

DETAILED DESCRIPTION

Reference will now be made in detail to the exemplary embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

It is understood that the exemplary devices and methods discussed beloware described in connection with vertebral bodies, such as, e.g., thelumbar and sacral vertebral bodies. However, unless specifically noted,the disclosed embodiments are not limited to use in connection withvertebral bodies, or any particular vertebral bodies. Instead, thedisclosed embodiments may have applicability in various parts of thebody where it is desired to correct misalignment between adjacentstructures. Moreover, the disclosed embodiments may be used in variousprocedures where the benefits of the described devices and methods aredesired.

Turning now to FIGS. 1A-1D, there is depicted an exemplary embodiment ofan intervertebral implant assembly 10, in accordance with an embodimentof the present disclosure. As alluded to above, the implant assembly 10may be used for, among other things, correcting misalignment of adjacentvertebral bodies, which may be commonly associated with, e.g.,spondylolisthesis. The implant assembly 10 may include an outer member20 and an inner member 50.

The outer member 20 may be configured to define a frame having asubstantially U-shaped configuration. The U-shaped configuration maydefine a cavity/opening 22 therein. As discussed in greater detailbelow, the outer member 20 may be configured to at least partiallyreceive at least a portion of the inner member 50 within cavity 22. Theouter member 20 may include a first component 24, which may be a frameor frame-like member. First component 24 may be configured to providestructural rigidity to outer member 20.

In one embodiment, component 24 may include a substantially U-shapedconfiguration that defines cavity 22. As shown in FIG. 1A, component 24may include a first leg 26, a second leg 28, and a connecting leg 30.Connecting leg 30 may define the base of the U-shaped configuration,with legs 26, 28 extending anteriorly therefrom. Connecting leg 30 mayinclude substantially planar anterior 32 and posterior 34 (shown in FIG.1B) surfaces. Similarly, connecting leg 30 may include substantiallyplanar superior 36 and inferior 38 (shown in FIG. 1D) surfaces. Inaddition, some embodiments of superior and inferior surfaces 36, 38 mayinclude a slant or taper extending away from the anterior surface 32 andnarrowing toward opening/cavity 22. That is, in some embodiments,portions of assembly 10 may include a tapering configuration. In suchembodiments, therefore, a width of posterior surface 34 may be smallerthan the width of anterior surface 32. In other embodiments, however,the width of posterior surface 34 may be larger than the width ofanterior surface 32. In further embodiments, a width of the anteriorsurface 32 may be substantially similar to a width of the posteriorsurface 34.

As noted above, first and second legs 26, 28 extend anteriorly away fromconnecting leg 30. It is contemplated that legs 26, 28 may besubstantially similar to one another. Indeed, in one embodiment, legs26, 28 may be effectively mirror images of each other. Thus, for thepurposes of efficiency, only first leg 26 will be described herein.However, those of ordinary skill will understand that leg 28 may includesome or all of the features of first leg 26. In addition, legs 26 and 28do not necessarily have to be identical to one another. In fact, legs 26and 28 may include differing configurations (not shown).

First leg 26 may include an extension portion 40 and a head portion 42.Extension portion 40 may be integrally formed with connecting leg 30 andextending anteriorly therefrom. In some embodiments, however, extensionportion 40 may be fixedly secured to connecting leg 30 by any suitablemeans known in the art. For example, extension portion 40 may be weldedto connecting leg 30. Extension portion 40 may include a substantiallytrapezoidal configuration. In other words, a transverse cross-sectionaldimension may gradually increase along the length of extension portion40. Extension portion 40 may include a superior surface 44 and aninferior surface 46. As discussed in greater detail below, both thesuperior 44 and inferior 46 surfaces may include geometrical featuresconfigured to promote gripping of tissue and/or bone surfaces. Forexample, the geometrical features may include pyramidal extensions 48rising away from the respective superior 44 and inferior 46 surfaces. Inanother embodiment, the surfaces 44, 46 may include peaks, valleys,barbs, tines, a roughened surface, or any configuration suitable forpromoting gripping of appropriate tissue and/or bone surfaces.

An anterior end of extension portion 40 may be integrally formed withhead portion 42. In some embodiments, however, head portion 42 may befixedly secured to extension portion 40 by, e.g., welding. Head portion42 may include a height larger than a height of connecting leg 30. Withparticular reference to FIG. 1A, head portion 42 may be configured toextend laterally away from extension portion 40 in the direction awayfrom cavity 22. Furthermore, like superior 44 and inferior 46 surfacesof extension portion 40, the superior 52 and inferior 54 surfaces ofhead portion 42 may include geometric features for aiding in thegripping of tissue or bone surfaces. In addition, the superior 52 andinferior 54 surfaces may include a stepped configuration, which allowshead portion 42 to gradually increase in a height dimension in theanterior direction. Although the depicted embodiment includes three (3)steps, those of ordinary skill in the art will understand that anysuitable number of steps may be provided to achieve the desired increasein height and rate of increase in height.

A posterior surface 56 of head portion 42 may be substantially planarwith the exception of a one or more tabs 58 protruding posteriorlytherefrom. Although the depicted embodiments illustrate only one tab 58protruding from posterior surface 56, those of ordinary skill in the artwill understand that any suitable number of tabs 58 may protrude fromthe posterior surface 56. Tab 58 may include any suitable dimensionand/or configuration. As will be discussed in greater detail below, tab58 may facilitate connection of first component 24 to second component60. Rather than including a protruding tab 58, head portion 42 mayinclude a recess (not shown) for receiving a correspondingly configuredinsert portion (not shown) extending from second component 60.

A lateral surface, e.g., outer lateral surface 62 of head portion 42 maybe substantially planar. In some embodiments, lateral surface 62 mayinclude at least one geometric feature 64 for allowing a tool to grip orotherwise manipulate assembly 10. Geometric feature 64 may include anysuitable configuration corresponding to an appropriate tool. In oneembodiment, geometric feature 64 may include a substantially rectangularnotch having rounded corners. The notch may include a depth into thelateral surface 62 of head portion 42. As shown in FIG. 1A, geometricfeature 64 may be disposed relatively closer to posterior surface 56than to anterior surface 66 of head portion 42.

Anterior surface 66 of head portion 42 may be substantially planar. Insome embodiments, anterior surface 66 may include at least onecounterbore 68 configured to at least partially receive a head of afastener, which will be described in greater detail below. Counterbore68 may be in communication with a coaxial hole extending through headportion 42, as shown in FIG. 1D. Counterbore 68 may be configured tofacilitate guiding a fastener (e.g., bone screw 80 described in greaterdetail below) through head portion 42 at a desired angle. In anembodiment, counterbore 68 and its corresponding coaxial hole may beconfigured to guide the fastener into a vertebral body in a convergingrelationship relative to the fastener associated with head portion 42 a.The angle of insertion can be varied between 35 degrees from thecephalad caudal direction to 10 degrees medial-lateral.

Head portion 42 may include a second counterbore 70 disposed adjacent tocounterbore 68. Second counterbore 70 also may be in communication withanother coaxial hole (not shown), which may not necessarily extend allthe way through head portion 42. Indeed, in the depicted embodiment,second counterbore 70 is in communication with a blind coaxial hole.Further, second counterbore 70 may be in communication with counterbore68. Stated another way, a portion of second counterbore 70 may open intocounterbore 68 and vice versa, as shown in FIG. 1A. As will be explainedin greater detail below, second counterbore 70 may include a fastenerrestricting mechanism 72. Second counterbore 70 may include a depthsufficient to allow fastener restricting mechanism 72 to be disposedcompletely within second counterbore 70 or at least flush with anteriorsurface 66 of head portion 42.

Fastener restricting mechanism 72 may be any suitable mechanism forpreventing a fastener, such as, e.g., bone screw 80, from becomingdisengaged from the vertebral body to which it is secured. For example,in one embodiment, fastener restricting mechanism 72 may be configuredto limit longitudinal displacement of bone screw 80. Fastenerrestricting mechanism 72 may include a screw (e.g., a set screw)disposed in a hole that is coaxial with second counterbore 70. In someembodiments, fastener restricting mechanism 72 may include a cam-styleblocking mechanism. For example, the fastener restricting mechanism 72may include a screw having a head having a greater width dimension thana remainder of the screw. The head of mechanism 72 may include a cutoutthat allows a head 82 of bone screw 80 to freely pass the head ofmechanism 72 when the cutout is disposed in the path of travel of head82. However, when fastener restricting mechanism 72 is rotated, thecutout may be moved away from the path of travel of head 82 and ablocking portion of mechanism 72 may be disposed in the path of travelof head 82, thereby preventing longitudinal movement of bone screw 80.Also, as is known in the art, the head 82 of bone screw 80 may include akeyed opening 81, which may be configured to receive acorrespondingly-sized tool for rotating bone screw 80.

As explained above, second leg 28 may include one or more features ofleg 26. Indeed, in some embodiments, second leg 28 may be an identicalmirror image of first leg 26.

In some embodiments, portions of first component 24 may be configured topromote bone tissue infiltration. For example, in one embodiment, thesuperior and inferior surfaces (or any other surfaces configured to bein contact with bony tissue) may include a porous configuration to allowbone ingrowth. In another embodiment, those surfaces of first component24 that are intended to be in contact with bony tissue may include asuitable coating, such as, e.g., hydroxyapatite, for promoting bonetissue ingrowth into portions of first component 24.

First component 24 may be fabricated via any method known in the art.For example, first component 24 (including first leg 26, second leg 28,and connecting leg 30) may be molded in a one-piece configuration. Inanother embodiment, portions of first component 24 may be discreetlyfabricated, and then secured together by any suitable means, including,but not limited to, welding.

First component 24 may be fabricated from any suitable biocompatiblematerial. For example, in one embodiment, all or a portion of firstcomponent 24 may be made of Titanium. Other suitable materials include,but are not limited to, stainless steel, nickel, silver, or any suitablealloy.

As alluded to above, outer member 20 may further include a secondcomponent 60. As shown in FIG. 1A, for example, second component 60 maybe disposed substantially about first component 24. More particularly,second component 60 may extend from posterior surface 56 of head portion42, along first leg 26, along connecting leg 30, and along second leg 28to the posterior surface 56 a of second head portion 42. In someembodiments, second component 60 may be formed of a one-piececonfiguration. In other embodiments, second component 60 may be formedof a plurality of discrete components secured to one another.

With continuing reference to FIG. 1A, the portions of second component60 adjacent head portions 42, 42 a, may include an opening or a cutout74 configured to receive tab 58 therein. Cutout 74 may include anysuitable configuration corresponding to a configuration of tab 58. Inone embodiment, cutout 74 may be configured to retain tab 58 therein viaa suitable interference or friction fit. In another embodiment, tab 58may be retained within cutout 74 with the aid of an adhesive. In an evenfurther embodiment, a mechanical fastener 76 may be used to retain tab58 within cutout 74. In those embodiments where a mechanical fastener 76may be used, one of a superior or inferior surface of second component60 may include an opening 78 for receiving the fastener 76. The opening78 may include a counterbore configured to completely receive a head offastener 76 therein. The counterbore 78 may lead to a coaxial openingextending through second component 60 at least between the counterboreand cutout 74. In such embodiments, tab 58 may include a correspondingopening or hole (not shown) for receiving a portion of fastener 76therein. In addition, both the hole in tab 58 and the coaxial holethrough second component 60 may include geometric features (e.g.,internal screw threads) configured to interact with correspondinggeometric features (e.g., external screw threads) on fastener 76 forretaining fastener, thereby retaining tab 58 within cutout 74.

As shown in FIG. 1B, second component 60 may include first and secondlateral portions 60 a, 60 b corresponding to head portions 42, 42 a.Anterior portions of lateral portions 60 a, 60 b may include width andheight dimensions corresponding approximately to those of head portions42, 42 a. In addition, as shown in FIG. 1A, lateral portions 60 a, 60 bmay include a posteriorly tapering configuration. That is, a height oflateral portion 60 at, e.g., a location adjacent head portion 42 may belarger than a height at, e.g., a location farther away from head portion42.

The superior and/or inferior surfaces of lateral portions 60 a, 60 b mayinclude one or more geometric configurations configured to promotefrictional interaction with adjacent bone or tissue surfaces. Forexample, the superior and/or inferior surfaces may include a pluralityof pyramid-like projections 69 and corresponding valleys. In otherembodiments, the superior and/or inferior surfaces may include, but arenot limited to, barbs, tines, hooks, a roughened surface, etc. Inaddition, or alternatively, the superior and/or inferior surfaces mayinclude a suitable porous structure configured to promote bone ingrowth.In addition, the superior and/or inferior surfaces may include a coatingfor promoting bone ingrowth. In one embodiment, the coating may includehydroxyapatite. Of course, any portion of assembly 10 may include anysuitable coating, including, but not limited to, coatings containingtherapeutic, antibiotic, and/or anesthetic agents.

Lateral portions 60 a, 60 b may be connected to one another via centralportion 60 c. Central portion 60 c may be disposed adjacent connectingleg 30. Central portion 60 c may include width and height dimensionssubstantially similar to connecting leg 30. In one embodiment, thesuperior 84 and anterior 86 surfaces of central portion 60 c may includea tapering configuration. Further, although the depicted embodiments donot illustrate any geometric features on the surfaces of central portion60 c, those of ordinary skill will readily recognize that one or moresurfaces of central portion 60 c may include any suitable geometricconfigurations and/or coatings.

Second component 60 may be made of any suitable biocompatible materials,including, but not limited to, thermoplastics, metals, composites,and/or alloys. In one embodiment, for example, second component 60 maybe made of polyether ether ketone (PEEK).

With renewed reference to FIG. 1A, for example, inner surfaces of legs26 and 28 may be substantially planar. In one embodiment, however, theinner surfaces of one or both of legs 26 and 28 may include a ledge orrail 88 disposed thereon. As will be discussed in greater detail below,rail 88 may be configured to slidably receive inner member 50. In someembodiments, rail 88 may be integrally fabricated with the innersurfaces of legs 26 and 28. In another embodiment, rail 88 may besecured to the inner surfaces of legs 26 and 28 via any suitable means.Although the depicted embodiment illustrates only one rail 88 on each ofthe inner surfaces of legs 26 and 28, those of ordinary skill in the artwill readily understand that any suitable number of rails 88 may beprovided in accordance with the principles of the present disclosure. Insome embodiments, instead of or in addition to a rail 88, the innersurfaces of legs 26 and 28 may be formed with a groove 77 for receivinga corresponding projection 79 from inner member 50. The groove 77 may beintegrally formed within the surfaces of legs 26 and 28, or the groovemay be cut (by, e.g., a laser) after legs 26 and 28 are formed.Moreover, although the depicted embodiment illustrates that a rail 88 isprovided on each of legs 26 and 28, some embodiments may only include asingle rail 88 provided on one of legs 26 and 28. In furtherembodiments, one of legs 26 and 28 may include a rail 88, and the otherof legs 26 and 28 may include a groove 77 as discussed above.

In addition to a mechanism (e.g., rail 88) for slidably receiving innermember 50, the inner surfaces of one or both of legs 26 and 28 mayinclude a mechanism for retaining a position of inner member 50 relativeto outer member 20. The mechanism for retaining inner member 50 relativeto outer member 20 may be any suitable mechanism known in the art. Forexample, in one embodiment, the inner surfaces of one or both of legs 26and 28 may include a ratchet mechanism 90, which will be discussed belowin greater detail. In another embodiment, the mechanism may include oneor more spring-loaded projections (not shown) configured to interactwith a plurality of grooves or openings (not shown). The spring-loadedprojections may be disposed on inner surfaces of legs 26 and 28, and thegrooves may be disposed on inner member 50, and vice versa.

In some embodiments, the mechanism for retaining a position of innermember 50 relative to outer member 20 may be configured to allow onlyunidirectional movement of inner member 50 relative to outer member 20.For example, ratchet mechanism 90 may comprise of plurality ofdirectional teeth 92 disposed on an inner surface of one of legs 26 and28. In addition, one or more pawls or other suitable catch(es) 94 may bedisposed on (e.g., extend from) inner member 50. The positioning of thedirectional teeth 92 and catch(es) 94 may be reversed in someembodiments. In addition, the ratchet mechanism 90 may include multiplerows of directional teeth 92. As will be explained in greater detailbelow, ratchet mechanism 90 may allow inner member 50 to be graduallyand progressively advanced into opening 22, while precluding innermember 50 from being withdrawn in the reverse direction.

With continued reference to FIGS. 1A-1D, inner member 50 may beconfigured to be at least partially received within opening 22 of outermember 20. Inner member 50 may include an anterior portion 100 with aplurality of legs 102 extending posteriorly away from anterior portion100. In one embodiment, the entirety of inner member 50 may beconfigured to be received within opening 22, such that anterior portion100 is made flush with head portions 42, 42 a, as shown in FIG. 2A. Forthe purposes of efficiency, only one of the plurality of legs 102 willbe described herein. However, those of ordinary skill in the art willunderstand that the other leg 102 may include any or all of thedescribed features. Indeed, in one exemplary embodiment, the pluralityof legs 102 may be substantially identical mirror images of eachanother.

Anterior portion 100 may include an anterior surface 103. Anteriorsurface 103 may be substantially planar. In one embodiment, anteriorsurface 103 may include a first counterbore 104 and a second counterbore106. The first counterbore 104 may be in communication with a coaxialhole (not shown), and may be configured to receive and retain afastener, such as, e.g., bone screw 80, therein. For example, a portionof first counterbore 104 and or the coaxial hole may include geometricfeatures (e.g., internal screw threads) configured to interact withgeometric features (e.g., external screw threads) disposed on bone screw80. As with counterbore 68 described above, first counterbore 106 may beconfigured to facilitate guiding a fastener (described in greater detailbelow) through anterior portion 100 at a desired angle.

The second counterbore 106 may be disposed adjacent and in communicationwith first counterbore 104. As described above, second counterbore 106may include one or more features of counterbore 70. For example, secondcounterbore 106 may be in communication with a coaxial hole (e.g., ablind coaxial hole) (not shown), and may be configured to receive andretain a fastener retaining mechanism 72 (described above) therein.

In addition, anterior portion 100 may be dimensioned so that thesuperior and/or inferior surfaces are substantially flush with therespective surfaces of head portions 42, 42 a, as shown in FIG. 2A, forexample.

Legs 102 may extend posteriorly from a posterior surface of anteriorportion 100, so as to define a substantially U-shaped configuration. Inone embodiment, legs 102 may be fabricated from a one-piece constructionwith anterior portion 100. In another embodiment, one or both of legs102 may be fixedly secured to a posterior surface of anterior portion100, via, e.g., welding or a suitable fastening mechanism, including,but not limited to, a mechanical fastener or an adhesive. Legs 102 maygenerally include a tapering configuration corresponding to associatedportions (e.g., legs 26, 28) of outer member 20. For example, legs 102may decrease in height when moving in the posterior direction.

As alluded to above, one or both of legs 102 may include portions ofratchet mechanism 90. For example, one or both of legs 102 may includeeither a plurality of directional teeth 92 or catches 94. In theillustrated embodiments, legs 102 include a single catch 94 extendinglaterally away from legs 102, as shown in FIG. 1B. The catch 94 mayinclude a hook-like configuration. Catch 94 may be configured to deformout of and into engagement with successive teeth 92. Accordingly, aportion of catch 94 may be elastic or spring-like. In some embodiments,legs 102 may include a plurality of catches 94. The catch 94 may beconfigured to interact with directional teeth 92 to retain inner member50 relative to outer member 20. As explained above, catch 94 may beconfigured to allow unidirectional relative movement between outermember 20 and inner member 50. That is, directional teeth 92 and catch94, collectively referred to as ratchet mechanism 90, may be configuredto only allow inner member 50 to move into opening 22, but not out ofit.

In addition, each of legs 102 may include an elastic or spring-likestabilizing member 87. The stabilizing member 87 may assist in guidinginner member 50 as it slides relative to outer member 20. In addition,stabilizing member 87 may be configured to exert tension against legs26, 28, respectively, to ensure inner member 50 remains centered withrespect to opening 22. Further, stabilizing member 87 may also act as aspring point for ratchet mechanism 90, allowing for a smooth flexing ofcatch 94.

The superior and/or inferior surfaces of inner member 50 may beconfigured to promote bone ingrowth. For example, one or more superiorand/or inferior surfaces of inner member 50 may include a porousstructure to facilitate tissue infiltration. In addition, the one ormore superior and/or inferior surfaces of inner member 50 may includeany suitable coating, such as, e.g., a coating of hydroxyapatite, atherapeutic agent, and/or an anesthetic.

The sides of inner member 50 may include one more slots and/or notches110, and/or projections 79, which may be configured to allow innermember 50 to slide on rail 88 of outer member 20. Of course, those ofordinary skill in the art will recognize that the exact design andconfiguration of the mechanism that allows inner member 50 to moverelative to outer member 20 may vary among the many available optionsknown in the art. The illustrated embodiments and configurationstherefore are only for exemplary purposes. For example, as shown in FIG.1A, each side of inner member 50 includes two notches 110, at least oneof which is configured to matingly receive rail 88. In addition, aprojection 79 may be configured to be received into a groove 77. Thenotches 110 may be disposed along an entire side of inner member 50, andmay be disposed on an outer sidewall of legs 102. In embodiments wherethe inner surfaces of legs 26 and 28 include multiple projections orrails, e.g., the outer sidewall of legs 102 would include correspondinggeometric features as well.

With reference now to FIGS. 2A and 2B, as discussed above, inner member50 is configured to move relative outer member 20, such that it maygradually move from the configuration depicted in FIGS. 1A-1D to, e.g.,the configuration depicted shown in FIGS. 2A-2B. As a result of ratchetmechanism 90, however, inner member 50 may be positioned in anyintermediate position between those shown in FIGS. 1A-1D and FIGS.2A-2B. As shown in FIG. 2A, inner member 50 may be dimensioned to becompletely received within opening 22, so that anterior surface 102 issubstantially flush with the anterior surfaces of head portions 42, 42a. As will be discussed below in greater detail, inner member 50 may bemoved relative to outer member 20 by any suitable method. For example,in one embodiment, inner member 50 may be moved by driving itsassociated screw 80 into a vertebral body. In another embodiment, theinner member 50 may be pushed into opening 22 by, e.g., a tool, untilinner member 50 is positioned in a desired location relative to outermember 20. Subsequently, a screw 80 may be inserted into counterbore 104and secured to a vertebral body, thereby securing inner member 50relative to outer member 20.

Furthermore, portions of inner member 50 and/or outer member 20 may beradiolucent or radiopaque as desired. In addition, assembly 10 mayinclude any suitable radiopaque markings necessary to assist withvisualizing assembly 10 within a patient's body.

Turning now to FIGS. 3A-3B, an exemplary method for correctingmisalignment of vertebral bodies in a patient's spine is depicted anddescribed herein. As shown in FIG. 3A, a first vertebral body VB1 mayhave slipped forward and out of alignment relative to a second vertebralbody VB2 disposed below first vertebral body VB1. Such slippage mayoccur for any number of reasons, including, but not limited to,age-related degeneration, physical trauma, congenital birth defect, orstress fractures caused by, among other things, excessive hyperextensionof the spine.

Prior to beginning a procedure to correct the misalignment betweenvertebral bodies VB1 and VB2, a physician or other healthcare providermay manually move vertebral body VB1 into correct alignment to gauge,among other things, the amount of correction needed and the appropriatepositioning of assembly 10 relative to vertebral body VB2. To correctthe aforementioned vertebral body misalignment, the physician or otherhealthcare provider may begin by accessing the targeted anatomicalstructures through any suitable approach known in the art. It iscontemplated that the devices described herein may allow for correctingvertebral misalignment via a solely anterior approach. Once thephysician accesses the targeted anatomical structures, he/she may beginby removing the native disk disposed in between of vertebral bodies VB1and VB2. Vertebral bodies VB1 and VB2 may include any vertebral bodiesin a patient's spine. In some cases, vertebral body VB1 may include theLumbar 5 (L5) vertebral body, and vertebral body VB2 may include theSacrum 1 (S1) vertebral body. The disk may be removed by any suitableprocedure known in the art, including, but not limited to, a discectomy.In some instances, the physician may roughen adjacent surfaces on eachof vertebral bodies VB1 and VB2 prior to positioning assembly 10 in theinterbody disk space between vertebral bodies VB1 and VB2. Assembly 10may be implanted in a pre-assembled stated with inner member 50connected to outer member 20. Further, during the procedure, theassembly 10 may not be disassembled. As alluded to above, the proceduremay be conducted via an anterior-only approach. That is, the assembly 10may be implanted and manipulated from only an anterior side of thepatient.

Once positioned appropriately on, e.g., vertebral body VB2, thephysician may use a tool (not shown) to engage opening 81 on theassociated screws 80 to drive screws 80 into vertebral body VB2 at apredetermined angle, so as to securely fasten outer member 20 tovertebral body VB2. Prior to engaging screws 80, however, if necessary,the physician may manipulate fastener restricting mechanism 72 to aconfiguration that allows screw heads 82 to pass by fastener restrictingmechanism 72. As shown in, e.g., FIG. 1D, screws 80 may be inserted intovertebral body VB2 in a converging relationship relative to one another.Once the screws 80 have properly secured outer member 20 to vertebralbody VB2, the fastener restricting mechanism 72 may be manipulated againto prevent screws 80 from becoming disengaged. Next, in someembodiments, bone cement or another similar substance may be placedwithin opening 22 of outer member 20. Subsequently, in one embodiment,inner member 50 may be manually pushed into cavity to effect the desiredamount of correction necessary to correct the misalignment of vertebralbodies VB1 and VB2. As noted above, inner member 50 may be gradually andstep-by-step advanced into opening 22 as catch 94 passes eachdirectional tooth 92. In another embodiment, bone screw 80 associatedwith inner member 50 may be gradually advanced into vertebral body VB1until the desired level of correction is achieved, as shown in FIG. 3B.Once the desired level of correction is achieved, a fastener restrictingmechanism 72 may be activated to prevent bone screw 80 of inner member50 from becoming disengaged.

With reference now to FIGS. 4A-4F, there are depicted additionalembodiments of devices for correcting misalignment of vertebral bodies,including, e.g., spondylolisthesis. Though the depicted embodimentscontemplate treating spondylolisthesis via an anterior approach, thoseof ordinary skill in the art will understand that any suitable approachis contemplated within the principles of the present disclosure. Asnoted above, each of the various embodiments disclosed herein mayinclude any of the features described in connection with the otherembodiments.

With specific reference to FIG. 4A, there is depicted a first vertebralbody VB1 and a second vertebral body VB2. In the illustrated embodiment,first vertebral body VB1 may be disposed above second vertebral bodyVB2. An embodiment of a device in accordance with the present disclosuremay include an interbody spacer 400 configured to be implanted withinthe interbody disk space between vertebral bodies VB1 and VB2. Spacer400 may include any suitable configuration. In one embodiment, spacer400 may include dimensions corresponding to first and second vertebralbodies VB1 and VB2. In addition, spacer 400 may include a substantiallysolid component made of, e.g., PEEK. In other embodiments, spacer 400may include a cage-like configuration with a substantially hollowinterior. For example, spacer 400 may be made of a plurality of wiresdefining an enclosure. The wires, or any portion of spacer 400, may bemade of any suitable materials, including, e.g., titanium, nickel,stainless steel, or any alloys thereof.

In one embodiment, one or more of the superior and/or inferior surfacesof spacer 400 may include one or more geometric features configured toallow spacer 400 to grip adjacent bony surfaces of vertebral bodies VB1and VB2. For example, the superior and/or inferior surfaces may includeprojections, such as, e.g., barbs, tines, spikes, and/or screws. In afurther embodiment, the superior and/or inferior portions of spacer 400may be configured to promote bone ingrowth. For example, one or both ofthe superior and/or inferior surfaces of spacer 400 may include a porousportion. In another embodiment, one or both of the superior and/orinferior surfaces of spacer 400 may include a suitable coating,including, e.g., a coating of hydroxyapatite. Spacer 400 may alsoinclude any other suitable coating (e.g., antibiotic, antiseptic,anesthetic, or otherwise therapeutic) known in the art. Further, spacer400 may be flexible and/or compressible. In other embodiments, spacer400 may be substantially rigid. A portion of spacer 400 may beradiopaque while other portions remain radiolucent. For example, inembodiments where spacer 400 is made of PEEK, the spacer 400 may includeone or more suitable radiopaque markers thereon.

In some embodiments, one or more dimensions of spacer 400 may beselectively adjustable. For example, a height, width, or diameter ofspacer 400 may be adjusted to suit a particular patient's anatomy.Spacer 400 may be adjusted by any means known in the art. In someembodiments, spacer 400 may be configured to expand and collapse. Insuch embodiments, spacer 400 may be expanded to desired dimensions. Forexample, spacer 400 may be an inflatable structure, which may beinflated until it expands to a desired dimension. In such cases, spacer400 may be inflated with any suitable material. For example, spacer 400may be inflated with a substance (e.g., an epoxy) configured to hardenor cure once spacer 400 is inflated to a desired dimension.

Spacer 400 may include a passageway or channel 402 therethrough. Channel402 may be formed by any suitable means known in the art. For example,spacer 400 may be molded with channel 402 therein. In anotherembodiment, channel 402 may be drilled or cut through spacer 400.Although the depicted embodiment illustrates a single channel 402, thoseof ordinary skill in the art will understand that spacer 400 may includeany suitable number of channels 402. Channel 402 may extend throughspacer 400 in any suitable direction or at any suitable angle. Forexample, channel 402 may extend at an angle configured to allow afastener inserted therethrough to bring vertebral bodies VB1 and VB2closer together. In addition, the angle may also cause the vertebralbodies to move laterally relative to one another. In those embodimentswhere a plurality of channels 402 are provided, the plurality ofchannels 402 may extend parallel to one another or at an angle relativeto one another. One or all of the plurality of the channels 402 may beconfigured to receive a fastener such as, e.g., elongate member 404.Channel 402 may be preformed in spacer 400 prior to implantation. Insome embodiments, however, channel 402 may be formed in spacer 400 afterimplantation. For example, a reamer (not shown) may be used to createchannel 402. Alternatively, channel 402 may be created by advancingelongate member 404 through spacer 400.

With continued reference to FIG. 4A, the disclosed embodiment mayfurther include an elongate member 404 inserted from vertebral body VB1through spacer 400 and into vertebral body VB2. In some embodiments,elongate member 404 may include a strut, rod, or screw. That is, theelongate member 404 may have any suitable configuration known in theart. Elongate member 404 may include one or more geometric features forretaining elongate member 404 within vertebral bodies VB1 and VB2. Suchfeatures may include, e.g., screw threads and/or a screw head 408. Inaddition, a distal end of elongate member 404 may be sharpened or mayterminate in a pointed end.

Elongate member 404 may be made of any suitable materials, including,e.g., titanium, stainless steel, nickel, or any suitable alloys. Inaddition, elongate member 404 may include tissue, such as, e.g., anallograft.

In the embodiment shown in FIG. 4A, a portion of vertebral body VB1 maybe removed by, e.g., reaming. For example, a conventional reamer may beused to create a passageway into vertebral body VB1. Further, a cavityfor accommodating screw head 408 may be also created in vertebral bodyVB1. In some embodiments, a passageway into vertebral body VB2 may bealso created. In addition, a thread cap (not shown) may be secured to abase of the passageway in vertebral body VB2 for receiving elongatemember 404.

In use, elongate member 404 may be inserted into vertebral body VB1,through spacer 400, and screwed into vertebral body VB2 with or withoutthe aid of a suitable thread cap. Doing so will cause spacer 400 tobecome compressed between vertebral bodies VB1 and VB2, as indicated byarrows 401 a and 401 b. Also, as a result of the angle of insertion ofelongate member 404, the vertebral bodies VB1 and VB2 may be movedlaterally relative to one another to correct any misalignment caused by,e.g., spondylolisthesis, as shown by arrows 407 a and 407 b. The degreeof correction necessary may determine the depth elongate member 404 isinserted into vertebral body VB2.

With reference now to FIG. 4B, there is depicted another embodiment of adevice for correcting vertebral body misalignment. The embodimentdepicted in FIG. 4B may include one or more features of the embodimentdepicted in FIG. 4A. For example, the embodiment of FIG. 4B may includea spacer 400 having a channel 402, and an elongate member 410. Elongatemember 410 of FIG. 4B may be substantially similar to the elongatemember 404. However, instead of a head 408, elongate member 410 mayinclude screw threads disposed on both ends thereof, with at least oneof the ends terminating in a pointed end, while the other terminates ina blunt end. The screw threads 412 on a superior end of elongate member410 may be configured to receive a nut 414 thereon for securing elongatemember 410 to vertebral body VB1. Nut 414 may include a through hole ora blind hole (not shown) therein. In embodiments where elongate member410 may be secured to a vertebral body (e.g., vertebral body VB1) vianut 414, the vertebral body may be further reamed to create acounterbore 411 for receiving nut 414. As those in art will readilyrecognize, counterbore 414 may include a diameter large enough tocompletely accommodate nut 414 and the corresponding terminal end ofelongate member 410 therein.

With reference to FIG. 4C, an angle of channel 402 through spacer 400,or the depth elongate member 410 is inserted into vertebral body VB2,may cause a superior end of elongate member 410 to protrude out of aperiphery of vertebral body VB1. In such cases, a cap 416 may beprovided to protect anatomical structures (e.g., nerves, blood vessels,and the like) from damage caused by the superior end of elongate member410 and/or an associated nut. Cap 416 may be any suitable structureconfigured for being disposed over an end of elongate member 410 tocreate a substantially atraumatic surface thereon. In one embodiment,cap 416 may define a cavity therein for placement over a superior end ofelongate member 410. The cavity may be configured to receive the end ofelongate member 410 and any associated nut. For example, cap 416 may bea rigid or flexible member configured to be cemented or otherwisesecured over the superior end of elongate member 410. In a furtherembodiment, cap 416 may include a gel or paste-like substance configuredto be applied about and over the superior end, and be molded or shapedto form an atraumatic external surface when dried or cured. The gel orpaste-like substance may be configured to cure upon exposure to certaintriggers, including, e.g., body chemistry and/or temperature.

As shown in FIG. 4D, e.g., an embodiment of a device for correctingvertebral misalignment may include lining a surface of counterbore 411with a staple or plate 420. Plate 420 may provide a rigid surface uponwhich nut 414 may rest. In addition, plate 420 may prevent rotation ofnut 414 from further damaging the native structure of the vertebralbody. Moreover, plate 420 may assist in preventing nut 414 fromdisengaging elongate member 410. For example, plate 420 may include acatch (e.g., a projection) (not shown) configured to prevent nut 414from reversing itself off of elongate member 410. In one embodiment, thecatch may include one or more features of the fastener restrictingmechanism described above.

Plate 420 may include any suitable configuration. For example, in oneembodiment, plate 420 may include a relatively small thickness. Inaddition, plate 420 may be made of any suitable material. For example,plate 420 may be made of a biocompatible metal, such as, e.g., titanium,stainless steel, nickel, nitinol, or any suitable alloy. In addition,plate 420 may be substantially malleable so as to allow plate 420 to beconformed to an inner surface of counterbore 411. Further, the materialof plate 420 may be configured to transition from a substantiallyflexible (e.g., foil-like) state to a substantially rigid state uponexposure to certain triggers, including, e.g., body chemistry and/ortemperature. Further, plate 420 may include a substantially constantthickness, or may include one or more different thicknesses, as shownin, e.g., FIG. 4E.

Plate 420 may be secured to the inside of counterbore 411 by anysuitable method known in the art. For example, plate 420 may beadhesively secured to counterbore 411 by, e.g., bone cement. In anotherembodiment, one or more mechanical fasteners may be used to secure plate420 to one or more portions of counterbore 411. In some embodiments, aportion 421 of plate 420 may extend out of counterbore 411 and along anexternal wall of vertebral body VB1, for example. In such embodiments,portion 421 may facilitate anchoring plate 420 to the vertebral body. Inaddition, portion 421 may prevent damage to weakened portions of thevertebral body structure by, e.g., a tool rotating nut 414. Further,although not shown, additional portions of plate 420 may extend out ofcounterbore 411 and along any external wall of vertebral body VB1.

Turning now to FIG. 4E, there is depicted yet another embodiment of adevice for correcting spinal misalignment. The embodiment depicted inFIG. 4E may include one or more of the features described in connectionwith the other embodiments discussed herein. The embodiment of FIG. 4Eincludes an adjustable passageway or channel 403. Channel 403 may bemade adjustable by any suitable means known in the art. For example,structures may be selectively positioned within or about an opening ofchannel 403 to alter an angle of channel 403 relative to spacer 400. Inthe embodiment of FIG. 4E, channel 403 may be formed in an insert 422that is movable relative to a remainder of spacer 400. Insert 422 mayinclude any suitable configuration known in the art. Insert 422 mayinclude a substantially spherical configuration configured to be movablydisposed in an appropriately configured recess in spacer 400. Insert 422may be made of any suitable material capable of allowing insert 422 tomove relative to spacer 400. For example, insert 422 may be made of aplastic configured to minimize friction between insert 422 and spacer400. In addition, an outer surface of insert 422 and/or an inner surfaceof the cavity within which it is disposed may include a suitablelubricious coating.

Insert 422 may be manipulated to set an angle of channel 403 throughspacer 400 by any suitable means. For example, prior to implantingspacer 400, a physician may manually set a position of insert 422. Inanother embodiment, insert 422 may be adjusted into position by elongatemember 410 as it travels through spacer 400. In an even furtherembodiment, a suitable tool may be employed to manipulate insert 422 insitu as desired.

Turning now to FIG. 4F, there is depicted yet another embodiment of adevice for correcting vertebral misalignment. The embodiment of FIG. 4Fmay include one or more features of the embodiment of FIG. 4E. Inaddition, the embodiment of FIG. 4E may allow for using a tool 450 to,among other things, manipulate insert 422 and guide elongate member 410therethrough.

As shown in FIG. 4F, tool 450 may include a first portion 452 and asecond portion 454. Tool 450 may function as a guide for orienting acannula 460 for appropriate insertion of elongate member 410. Firstportion 452 may be integrally formed with second portion 454. In someembodiments, however, first portion 452 may be rigidly connected tosecond portion 454 by, e.g., welding. An end 453 of first portion 452opposite to the connection with second portion 454 may be configuredfollow an angle of insert 422. For example, end 453 may include a curvedface 455 having an arc angle corresponding to an outer surface of insert422. End 453 may include any suitable configuration for following anangle of insert 422. Thus, as insert 422 is manipulated to select adesired angle for channel 403, guide 450 may be accordingly adjusted,thereby setting a corresponding angle for insertion of elongate member410 via cannula 460. As explained above, end 453 is configured to followan angle of insert 422. Consequently, first portion 452 and secondportion 454 may be adjusted as insert 422 is adjusted. End 457 of secondportion 454 may be configured to be removably secured to an insertioncannula 460. Thus, as guide 450 is moved, cannula 460 may be accordinglyoriented to correspond to the angle of channel 403.

With reference now to FIGS. 5A-5B, a method of using one or more of theembodiments of FIGS. 4A-4F is illustrated and described herein. As notedabove, the methods and devices disclosed herein may be used to, amongother things, correct misalignment of vertebral bodies, e.g.,spondylolisthesis. Although the described method corrects vertebralmisalignment via an anterior approach, those of ordinary skill in theart will understand that a posterior approach may be used additionallyor alternatively. Further, although the described embodiments discussmoving a superior vertebral body relative to an inferior vertebral body,the inferior vertebral body may be moved additionally or alternatively.

With reference to FIG. 5A, an interbody device 500 is depicted between asuperior vertebral body VB1 and an inferior vertebral body VB2. In somecases, the superior vertebral body VB1 may be the L5 vertebral body, andthe inferior vertebral body may be the S1 vertebral body. As notedabove, however, prior to positioning interbody device between vertebralbodies VB1 and VB2, the native disk may be removed by any suitableprocedure. The inferior surface of vertebral body VB1 and the superiorbody of vertebral body VB2 may be roughened to promote fusion (e.g.,ossification) with interbody device 500. To assist with fusion,interbody device 500 may include a plurality of geometric features 502disposed on one or both of the superior and/or inferior surfaces ofinterbody device 500. The geometric features 502 may include anysuitable configuration and may include barbs, tines, spikes, screws, andthe like. In some embodiments, a suitable adhesive (e.g., bone cement)may be used to fixedly connect the interbody device to the adjacentsurfaces of one or more of vertebral bodies VB1 and VB2. For example,bone cement may be used to secure interbody device 500 to the superiorsurface of vertebral body VB2.

The interbody device 500 may include a one-piece construction. In someembodiments, however, the interbody device 500 may include twocomponents fixedly joined together. The components of interbody device500 may be made of any suitable material including, but not limited to,titanium, stainless steel, PEEK, nickel, or any suitable alloys.Interbody device 500 may further include a channel 503 extending at anangle through interbody device. As well be explained in greater detailbelow, channel 503 may be configured to receive an elongate member, suchas, e.g., a screw 504 therethrough. In some embodiments, an angle atwhich channel 503 extends through interbody device 500 may beadjustable.

Prior to inserting screw 504, however, a passageway 506 may be createdthrough vertebral body VB1 via a suitable reamer. In some embodiments, asimilar passageway may be created in vertebral body VB2 as well. Inaddition, a counterbore 508 in communication with passageway 506 may becreated to receive head 505 of screw 504 therein. The counterbore 508may be created by any suitable means, including, e.g., reaming. In someembodiments, however, only counterbore 508 may be created. Thepassageway 506 may be created by screw 504 as it is being driven throughvertebral body VB1. Next, a plate 510, which may be similar to plate 420discussed above, may be disposed in counterbore 508. As shown in FIG.5A, plate 510 may include a through opening in communication withpassageway 506. In addition, as shown in FIG. 5B, portions of plate 510may extend out of counterbore 508 and adjacent one or more externalwalls of vertebral body VB1. Next, screw 504 may be advanced throughvertebral body VB1, interbody device 500, and into vertebral body VB2.As screw 504 is advanced and tightened, the angle of insertion of screw504 (resulting from the angle of channel 503) may cause vertebral bodyVB1 to move posteriorly and inferiorly relative to vertebral body VB2,thereby moving vertebral body VB1 into proper alignment with vertebralbody VB2.

Turning now to FIGS. 6A-6B, there is depicted another embodiment of adevice assembly 600 for correcting misaligned vertebral bodies, inaccordance with the present disclosure. Assembly 600 may include any ofthe features described in connection with the other embodimentsdisclosed herein. For example, assembly 600 may include any or all ofthe features of assembly 10 described above. Assembly 600 includes aframe member 602. Frame member 602 may include any suitableconfiguration for disposal in the interbody disk space between twoadjacent vertebral bodies, such as, e.g., the L5 and S1 vertebralbodies. Of course, frame member 602 may be configured for disposalbetween any other two adjacent vertebral bodies.

Frame member 602 includes a posterior end 601 and an anterior end 603.In addition, frame member 602 includes a central section 604, a rightlateral section 606, and a left lateral section 608. The “right” and“left” designations are assigned when assembly 600 is oriented anddisposed in the interbody disk space between two adjacent vertebralbodies, for example.

Central section 604 includes a longitudinal member 610 defining a lumen612 therethrough. Lumen 612 may be in communication with an openingdisposed in an anterior end face 617 of longitudinal member 610. Theanterior end face 617 may be configured to receive a friction ring 615thereon, which will be described in greater detail below. In thedepicted embodiment, longitudinal member 610 may include a substantiallycylindrical configuration having flanges 614 extending laterally awaytherefrom. Those of ordinary skill will understand that longitudinalmember 610 may not be limited to a cylindrical configuration. In fact,longitudinal member 610 may include any suitable configuration known inthe art. Lumen 612 may be a substantially circular lumen configured,e.g., to receive a suitable fastener therein. However, lumen 612 mayinclude any suitable configuration. Lumen 612 may extend an entirelength of longitudinal member 610. In some embodiments, however, lumen612 may only extend along a portion of longitudinal member 610. In someembodiments, lumen 612 may include suitable geometric features thereinfor interacting and retaining a fastener received therein. In oneembodiment, the geometric features may include internal screw threads.Further, as can be seen in FIGS. 6A-7B, longitudinal member 610 mayinclude a through hole 616 extending from a superior external surface oflongitudinal member 610 through lumen 612 and to an inferior externalsurface of longitudinal member 610. Through hole 616 is utilized in thepeening process for the central actuator or longitudinal member 610.Once the longitudinal member 610 is threaded into through hole 698, aportion of the male threads are deformed via through hole 616 therebypreventing the back out of the longitudinal member from the innermember. Further, both longitudinal member 610 and lumen 612 may includesubstantially constant cross-sectional diameters. However, those ofordinary skill in the art will understand that the diameters of eitherlongitudinal member 610 or lumen 612 may vary along the lengths thereof.For example, the diameters of one or both of longitudinal member 610 andlumen 612 may reduce when moving posteriorly from anterior end 603.

Flanges 614 may be disposed adjacent a central longitudinal axis oflumen 612. As shown in FIG. 6A, e.g., the transition from thesubstantially cylindrical outer surface of longitudinal member 610 toflanges 614 may be substantially smooth. In addition, each of flanges614 may be integrally formed with longitudinal member 610. However, insome embodiments, flanges 614 may be secured to longitudinal member 610by, e.g., welding. Flanges 614 may include a generally rectangularcross-sectional configuration. However, one or both of flanges 614 mayinclude any suitable configuration. In addition, the configuration offlanges 614 may not be identical to one another. For example, a leftflange 614 may include a rectangular cross-sectional configuration,while the right flange may include a trapezoidal configuration (notshown).

Central section 604 may further include a posterior portion 618.Posterior portion 618 may extend posteriorly from longitudinal member610. In addition, posterior portion 618 may extend farther in thesuperior direction than both of flanges 614 and longitudinal member 610.Posterior portion 618 may also extend farther in the inferior directionthan both of flanges 614 and longitudinal member 610. Further, one orboth of anterior surface 620 and inferior surface (not shown) ofposterior portion 618 may be slanted to provide posterior portion 618with a tapered configuration. Still further, a posterior surface (notshown) of posterior portion 618 may be substantially planar.

Central section 604 may be integrally formed with one or both of rightlateral section 606 and left lateral section 608. However, in someembodiments, the right and left lateral sections 606, 608 may be securedto central section 604 by any suitable means known in the art,including, e.g., welding.

With reference primarily to FIG. 6B, the right and left lateral sections606, 608 may include substantially similar features. Indeed, the rightand left lateral sections 606, 608 may be effectively mirror images ofone another. For the purposes of efficiency, therefore, only rightlateral section 606 will be described herein. However, those of ordinaryskill in the art will understand that the right and left lateralsections 606, 608 also may include differing configurations (not shown).

Originating from approximately the location of the interface betweenposterior portion 618 and longitudinal member 610/flanges 614, anextension member 622 may extend laterally away from central section 604.As shown in FIG. 6B, extension member 622 may first extend laterallyaway from central section 604 and then curve to extend in the anteriordirection. That is, extension member 622 may include a first portion 622a extending substantially perpendicularly to longitudinal member 610,and a second portion 622 b extending substantially parallel to centralsection 604. First and second portions 622 a and 622 b may be connectedby a central portion 622 c. Central portion 622 c may be curved, asshown in FIG. 6B. However, central portion 622 c may be effectivelyeliminated and first and second portions 622 a and 622 b may be joinedby a right angle elbow (not shown). As can be seen in FIG. 6B, e.g.,extension member 622 and longitudinal member 610 may define a pluralityof through openings 605 therebetween. The openings 605 may be configuredto receive bone cement therein during an implantation procedure.

Extension member 622 may include a substantially planar internal surface623. In addition, extension member 622 may include a curved externalsurface 625. However, those of ordinary skill will understand that anysuitable configuration may be employed for internal and externalsurfaces 623, 625. Further, extension member 622 may includesubstantially planar superior and inferior surfaces. However, in someembodiments, the superior and inferior surfaces of extension member 622may include suitable geometric configurations for receiving andretaining an endplate, as discussed in greater detail below. As shown inFIG. 6B, first portion 622 a may include a hole 624 for facilitatingretention of the aforementioned endplate. Hole 624 may include suitablegeometric configurations for retaining a fastener therein. In oneembodiment, hole 624 may include internal threads (not shown) configuredto cooperate with a screw (not shown).

Second portion 622 b of extension member 622 may include one or moregeometric features to assist with retaining the aforementionedendplates. In one embodiment, one or both of the superior and/orinferior surfaces of second portion 622 b may include a rib 626. Rib 626may include any suitable configuration known in the art. For example,rib 626 may include a rounded projection extending away from therespecting superior/inferior surfaces. In some embodiments, rib 626 mayinclude a length along a substantial portion of second portion 622 b.However, rib 626 may not necessarily extend the full length of secondportion 622.

An anterior end portion of extension member 622 may be integrally formedwith an enlarged head portion 628. Head portion 628 may include any ofthe features described above in connection with head portions 42, 42 a.For example, in one embodiment, a lateral face of each portion 628 mayinclude a geometric feature 630 substantially similar to geometricfeature 64 described above. In particular, geometric feature 630 mayinclude a notch for allowing a tool (not shown) to grip and manipulateassembly 600. Further, superior and inferior surfaces of head portion628 may include one or more geometric features 632 configured toincrease friction between assembly 600 and adjacent bony surfaces. Thegeometric features 632 may include a plurality of pyramid-likeprojections and corresponding valleys. In other embodiments, thesuperior and/or inferior surfaces may include, but are not limited to,barbs, tines, hooks, etc. In addition, or alternatively, the superiorand/or inferior surfaces may include a suitable porous structureconfigured to promote bone ingrowth. Further, the superior and/orinferior surfaces may include a coating for promoting bone ingrowth. Inone embodiment, the coating may include hydroxyapatite. Of course, anyportion of assembly 600 may include any suitable coating, including, butnot limited to, coatings containing therapeutic, antibiotic, and/oranesthetic agents.

The anterior surface of head portion 628 may define at least twocounterbores 634, 636. Counterbore 634 may be in communication with acoaxial hole extending through head portion 628 at an angle relative toa longitudinal axis (not shown) of central section 604 (e.g.,longitudinal member 610). Counterbore 634 may be substantiallyspherical, and configured to receive a spherical head of a fastener(described below in greater detail) therein. In one embodiment,counterbore 634 and its associated coaxial hole may be configured toguide the received fastener at an angle in the inferior direction awayfrom frame member 602. In addition, the counterbore 634 and itsassociated coaxial hole may be configured to guide the received fastenertoward a central vertical axis (not shown) of frame member 602. Thus,the fasteners received in the two depicted head portions 628 may bedisposed in a converging relationship relative to one another. Asdescribed below, the fasteners received in head portions 628 may includesuitable bone screws 638.

Counterbore 636 may be relatively smaller in diameter than counterbore634. In addition, counterbore 636 may be in communication with a blindcoaxial hole (not shown). Counterbore 636 may be configured to receivetherein a set screw 640 including a threaded portion 640 a and a headportion 640 b. Head portion 640 b may be configured to include acam-style blocking mechanism, as described above. Indeed, set screw 640may be substantially similar to fastener restricting mechanism 72. Moreparticularly, head portion 640 b may include a cut-out portion 640 cconfigured to allow bone screw 638 to pass by set screw 640 when cut-outportion 640 c is disposed in the travel path of bone screw 638. However,if set screw 640 is rotated to move cut-out portion 640 c out of thetravel path of bone screw 638, a portion of head portion 640 b may abuta head of bone screw 638, thereby restricting its longitudinal movement.Those of ordinary skill will readily understand that any suitablemechanism for preventing bone screw 638 from reversing itself out ofengagement may be utilized in accordance with the principles of thepresent disclosure.

Head portions 628 may be connected to an anterior end of central section604 via central connections 639. Central connections 639 may include anysuitable configuration for supporting head portions 638. For example,central connections 639 may include substantially planar anteriorsurfaces 641, which may or may not be disposed flush with anteriorsurface 617. Indeed, in some instances, anterior surfaces 641 may beraised (by, e.g., a dimension corresponding to a thickness of frictionring 615) relative to anterior surface 617 to provide a seat forfriction ring 615. Further, the inferior 646 surfaces of centralconnections 639 may include suitable geometric configurations forincreasing friction relative to an adjacent bony surface, as describedherein. With reference to FIG. 6B, anterior surfaces 617, anteriorsurfaces 641, and lateral surfaces of head portions 628 may define acavity dimensioned for receiving an anterior head portion 672 of areducing plate 670 therein, as described in greater detail below.

With continuing reference to FIG. 6B, each extension member 622 may beconfigured to receive an end plate 642 thereon. End plate 642 mayinclude any suitable configuration for being disposed about extensionmember 622. End plate 642 may include a first portion 642 a, a secondportion 642 b, and a third portion 642 c connecting the first and secondportions 642 a, 642 b. First, second, and third portions 642 a, 642 b,and 642 c may be formed integrally with one another. In otherembodiments, however, first, second, and third portions 642 a, 642 b,and 642 c may be fixedly secured to one another by any suitable meansknown in the art.

First portion 642 a may be configured to be received on first portion622 a of extension portion 622. Accordingly, first portion 642 a mayinclude an internal channel 644 having internal geometry correspondingto an external geometry of first portion 622 a. The channel 644 may beconfigured to extend from a first terminal end face of end plate 642 toa second terminal end face of end plate 642. In addition, channel 644may be configured to receive extension member 622 therein via an opening645 in an external wall of end plate 642. Like channel 644, opening 645also may be configured to extend from a first terminal end face of endplate 642 to a second terminal end face of end plate 642. In oneembodiment, end plate 642 may be substantially flexible such that it mayopen in a clam-like manner, thereby enlarging opening 645 so thatextension member 622, and rib 626, may be received in channel 644.Further, a depth of channel 644 and opening 645 may be dimensioned suchthat when end plate 642 is disposed about extension member 622, therespective surfaces of end plate 642 disposed above and below opening645 are flush with surface 623 of extension member 622.

First portion 642 a may be dimensioned such that its superior andinferior surfaces are flush with respective surfaces of posteriorportion 618. For example, the superior and inferior surfaces of firstportion 642 a may include a slant or taper similar to the slant/taper ofsurface 620. First portion 642 a may also include a hole 650 configuredto receive a fastener (e.g., a set screw) for fixedly securing end plate642 to extension member 622.

Like first portion 642 a, second and third portions 642 b, 642 c may beconfigured to be disposed about second and third portions 622 b, 622 cof extension member 622. As explained above, channel 644 may include asuitable internal geometry for cooperating with an external geometry ofextension member 622. Thus, the portion of channel 644 in second portion642 b may include cutouts for accommodating one or more rib(s) 626. Inaddition, as shown in FIGS. 6A-6B, end plate 642 may be configured toprogressively increase in height from a posterior portion to an anteriorportion, such that its anterior end may be substantially similar to aposterior end face of head portion 628. Further, the superior andinferior surfaces of end plate 642 may include any suitable geometricconfigurations (e.g., rows of directional teeth, barbs, pyramids, etc.)configured to increase friction between end plate 642 and an adjacentbony surface.

End plate 642 may be fabricated via any suitable method known in theart. For example, end plate 642 may be molded or extruded. In addition,end plate 642 may be made of any suitable material. In one embodiment,end plate 642 may be made of a suitable organic polymer thermoplastic,such as, e.g., PEEK. In addition, one or more surfaces of end plate 642may be configured to promote bone ingrowth. For example, superior and/orinferior surfaces of end plate 642 may include a porous structure tofacilitate tissue infiltration. In addition, surfaces of end plate 642may include any suitable coating, including, but not limited to,hydroxyapatite and/or coatings containing therapeutic, antibiotic,and/or antiseptic agents.

With continuing reference to FIGS. 6B and 6C, e.g., assembly 600 mayfurther include a reducing plate 670. Reducing plate 670 may include ananterior head portion 672. Anterior head portion 672 may include anysuitable configuration. For example, anterior head portion 672 may bedimensioned to be received in the cavity defined by anterior surfaces617, anterior surfaces 641, and lateral surfaces of head portions 628described above, such that an anterior-most surface of reducing plate670 may be substantially flush with respective surfaces of head portions628 when reducing plate 670 is received in the aforementioned cavity.

Reducing plate 670 may define a mechanism for being received slidinglyon longitudinal member 610. For example, in one embodiment, reducingplate 670 may include a plurality of extension plates extendingposteriorly from a posterior surface of anterior head portion 672. Theplurality of plates may include an inferior extension plate 674 and asuperior extension plate 676. Although only two extension plates 674,676 are depicted, those of ordinary skill in the art will understandthat any suitable number of extension plates 674, 676 may be provided.Extension plates 674, 676 may be spaced from one another to define achannel 678 therebetween. In some embodiments, channel 678 may be aclosed channel (not shown). In such embodiments, lateral edges ofextension plates 674, 676 may be joined together by, e.g., a wall (notshown). However, in the depicted embodiment, channel 678 is depicted asa channel having open side walls. The channel 678 may include a geometrycorresponding to an outer geometry of longitudinal member 610 andflanges 614 so that reducing plate 670 may be slidably received onlongitudinal member 610, as shown in FIG. 6A. In addition, extensionplates 674, 676 may include a length such that posterior-most surfacesof extension plates 674, 676 abut anterior surfaces of posterior portion618 when anterior head portion 672 is fully received within the cavitydefined by anterior surfaces 617, anterior surfaces 641, and lateralsurfaces of head portions 628 described above.

The inferior surface 702 of inferior extension plate 674 may beconfigured to receive an end plate 706 thereon. Accordingly, surface 702may include one or more geometric features configured to retain endplate 704 on surface 702. In one embodiment, end plate 704 may be slidonto surface 702. Accordingly, surface 704 may include a central raisedportion 707 flanked by a stepped portion on either side. The centralraised portion may define a rail along which end plate 704 may slide.The superior surface (not shown) of superior extension plate 676 mayinclude features similar to those of surface 702.

End plates 706 may be configured to be received on extension plates 674,676. End plates 706 may include any suitable configuration. Further, theconfiguration of each end plate 706 may be substantially similar.Accordingly, for the purposes of efficiency, only one end plate 706 willbe described hereafter. In one embodiment, end plate 706 may be formedof a one-piece construction by, e.g., molding or extrusion. Further, endplate 706 may be formed of any suitable material, including, e.g., asuitable organic polymer thermoplastic, such as, e.g., PEEK. Inaddition, end plate 706 may include a generally tapering configuration.That is, as shown in FIG. 6B, a thickness of a posterior portion of endplate 706 may be smaller than a thickness of an anterior portion of endplate 706. An outer side of end plate 706 may include a plurality ofsuitable geometric features configured to increase friction between endplate 706 and adjacent bony surfaces. The geometric features mayinclude, e.g., projections, teeth, barbs, tines, spikes, and the like.For example, as shown in FIG. 6B, end plate 706 may include a pluralityof rows of teeth.

An inner side of end plate 706 may define a groove 708 for beingdisposed about central portion 707, so that end plate 706 may bereceived thereon. Accordingly, groove 708 may be appropriatelydimensioned and configured. In one embodiment, groove 708 may include asubstantially T-shaped configuration. That is, as shown in FIG. 6B,e.g., sides of groove 708 may extend into side walls of end plate 706 todefine a portion of groove 708 being covered by overhang 708 b. Further,overhang 708 b may be configured to be received in appropriatelyconfigured recesses on either side of central portion 707 so as tofrictionally retain end plate 706 on extension members 674, 676.

An anterior-most surface 680 of anterior head portion 672 may include aplurality of counterbores therein. For example, as shown in FIG. 6C,surface 680 may include four counterbores 682, 684, 686, and 688, eachof which may be in communication with one another. Counterbores 682 and684 may be substantially similar to each other and therefore will bedescribed together.

Counterbores 682 and 684 may be in communication with respective coaxialholes (not shown) extending through anterior head portion 672.Counterbores 682 and 684 and/or their respective coaxial holes mayinclude suitable geometric features (e.g., internal screw threads) forretaining a suitable fastener (e.g., a bone screw 690) therein.Counterbores 682 and 684 may be substantially spherical in configurationso as to at least partially accommodate spherical heads 692 of bonescrews 690. Those of ordinary skill in the art will understand that anysuitable fasteners may be used in place of bone screws 690. In oneembodiment, counterbores 682, 684 and their respective coaxial holes maybe configured to guide bone screws 690 received therein in a superiordirection at an angle relative to a longitudinal axis (not shown) oflumen 612. In addition, counterbores 682, 684 and their respectivecoaxial holes may be configured to guide bone screws 690 receivedtherein away from a central vertical axis (not shown) of frame member602. Thus, the fasteners received in counterbores 682 and 684 may bedisposed in a diverging relationship relative to one another. In otherembodiments, the fasteners may be disposed in a converging relationshiprelative to one another.

Counterbore 686 may be in communication with a coaxial through hole 698(shown in FIGS. 7A-7B). When reducing plate 670 is received overlongitudinal member 610, counterbore 688 and hole 698 may be incommunication with lumen 612 for collectively receiving actuator 700therein. One or both of counterbore 686 and through hole 698 may includegeometric features (e.g., internal screw threads) for retaining actuator700 therein. Further, as shown in FIG. 6A, counterbore 686 may bedimensioned to completely receive a head 700 a of actuator 700. As willbe described in greater detail below, actuator 700 may be used toposition reducing plate 670 relative to frame member 602, so as tocorrect vertebral misalignment.

Counterbore 688 may be in communication with a coaxial blind hole 696(shown in FIGS. 7A-7B) for receiving a set screw 694 incorporating aplurality of the cam-style blocking mechanisms described above. Thecoaxial blind hole 696 may include suitable geometric features (e.g.,internal screw threads) for retaining set screw 694 therein. Those ofordinary skill will readily understand that instead of set screw 694,any suitable fastener restricting mechanism may be used in accordancewith the principles of the present disclosure. Set screw 694 may includeany of the features of fastening restricting mechanism 72 describedabove. Further, it is contemplated that set screw 694 may be configuredto simultaneously restrict one or more of bone screws 690 and actuator700 (discussed below in greater detail) from longitudinal travel. Forexample, in one embodiment, a head 694 a of screw 694 may include aplurality of cutouts 694 c. As explained above, cutouts 694 c may allowthe heads of screws 690 and/or actuator 700 to pass head 694 a of screw694 when the cutouts 694 c are positioned in the path of travel ofscrews 690 and/or actuator 700, respectively. However, when cutouts 694c are moved out of the path of travel of screws 690 and/or actuator 700,a portion of head 694 a may interfere with the heads of screws 690and/or actuator 700, thereby restricting their longitudinal movement.Cutouts 694 c may be moved into and out of the travel paths by rotatingscrew 694 within hole 696 via, e.g., any suitable tool known in the art.

Actuator 700 may be any suitable actuator known in the art. For example,actuator 700 may be a threaded bolt or screw including a head 700 ahaving an opening 700 b therein for allowing a tool to selectivelyrotate actuator 700. Actuator 700 may also include a shaft 700 cextending away from head 700 a from a side of head 700 a opposite toopening 700 b. The shaft 700 c may include suitable geometric features(e.g., internal screw threads) for retaining actuator 700 in, e.g.,lumen 612. As shown in FIGS. 7A-7B, actuator head 700 a may be receivedin counterbore 688. In addition, shaft 700 c may be received throughhole 798 so that it may extend between extension plates 674, 676,through an opening 619 in friction ring 615 and into lumen 612.

Friction ring 615 may include any suitable structure configured tothreadingly receive shaft 700 c of actuator 700. In some embodiments,friction ring 615 may be made of a suitable organic polymerthermoplastic, such as, e.g., PEEK. Friction ring 615 may be formed byany suitable process known in the art, including, e.g., molding,machining, or extrusion. As noted above, friction ring 615 may includean opening 619 corresponding to lumen 612. In addition, friction ring615 may be configured to be disposed adjacent surface 617 oflongitudinal member 610. In one embodiment, friction ring 615 may bemade integrally with surface 617. In another embodiment, friction ring615 may be secured to surface 617 by, e.g., a suitable adhesive.

With reference now to FIG. 6B, an inferior surface 720 of anterior headportion may include an opening 722 in communication with a slot. Theslot may be in communication with counterbore 688. In one embodiment,opening 722 may be configured to receive therein a blocking plate 730.Blocking plate 730 may include a substantially square or rectangularconfiguration. However, one side of blocking plate 730 may include ageometric feature 732 configured to surround and engage head 700 a ofactuator 700. Geometric feature 732 may be configured to engage head 700a in the manner a wrench may engage the head of a nut, as will beappreciated by those of ordinary skill in the art. Blocking plate 730may be made of any suitable material known in the art, including, butnot limited to, titanium, stainless steel, nickel, and/or any suitablealloys. Further, blocking plate 730 may be dimensioned such that whengeometric feature 732 engages with head 700 a, blocking plate 730 isreceived completely within opening 722. Further, blocking plate 730 maybe secured within opening 722 and its associated slot by any means knownin the art. For example, a suitable adhesive (not shown) may be used tofix blocking plate 730 into opening 722.

Furthermore, portions of assembly 600 may be radiolucent or radiopaqueas desired. In addition, assembly 600 may include any suitableradiopaque markings necessary to assist with visualizing assembly 600within a patient's body.

Assembly 600 may be used to correct misalignment of adjacent vertebralbodies (e.g., the L5 and S1 vertebral bodies), including, but notlimited to, spondylolisthesis. Assembly 600 may be pre-assembled withreducing plate 670 thereon prior to implantation. Prior to implantingassembly 600 within a patient, however, a patient's native disc may befirst removed by, e.g., a discectomy procedure. Next, the surfaces ofthe vertebral body immediately adjacent the interbody disk space may beroughened, as is known in the art. Subsequently, frame member 602 may bepositioned in the interbody disk space. Prior to positioning framemember 602, however, a physician or other healthcare provider maymanually manipulate the dislocated vertebral bodies into properalignment so as to identify an appropriate positioning of frame member602 relative to, e.g., an inferior vertebral body. Once appropriatelypositioned, screws 640 may be rotated so that cutouts 640 c arepositioned in the path of travel of bone screws 638, and bone screws 638may be inserted into counterbores 634 to fasten frame member 602 to aninferior vertebral body. Screws 640 may be once again rotated to movecutouts 640 c out of the path of travel of screws 638, so that aremaining portion of a head of screw 640 may engage the heads of screw638 to retain them in position.

Next, screw 694 may be manipulated to dispose cutouts 694 c in the pathof travel of bone screws 690. Subsequently, bone screws 694 may beadvanced into counterbores 682 and 684 and into a superior vertebralbody to secure reducing plate 670 to the superior vertebral body. Then,screw 694 may be manipulated to move cutouts 694 c out of the path oftravel of screws 690, so that a remaining portion of head 694 a mayengage the heads 692 of screws 690 to retain them in position. Head 694a may also function to restrict longitudinal movement of actuator 700.

Subsequently, in some embodiments, bone cement may be disposed inopenings 605, as desired. Next, any displacement between the superiorand inferior vertebral bodies may be corrected by gradually turningactuator 700 to move reducing plate 670 in the posterior direction overlongitudinal member 610. Once the desired amount of correction isachieved, actuator 700 may be fixed in place so that a position ofreducing plate 670 is fixed relative to frame member 602. Actuator 700may be fixed in place my manipulating screw 694 so that, in addition torestricting movement of screws 690, screw 694 also restricts furthermovement of actuator 700. Further, blocking plate 730 may be insertedinto and secured (via, e.g., an adhesive) within opening 722, such thatfeature 732 engages actuator head 700 a and prevents it from rotating.Any cement inserted into openings 605 may be allowed to cured and theprocedure may be completed as customary in the art.

While principles of the present disclosure are described herein withreference to illustrative embodiments for particular applications, itshould be understood that the disclosure is not limited thereto. Thosehaving ordinary skill in the art and access to the teachings providedherein will recognize additional modifications, applications,embodiments, and substitution of equivalents all fall within the scopeof the embodiments described herein. Accordingly, the invention is notto be considered as limited by the foregoing description.

We claim:
 1. A vertebral implant, comprising: an assembly configured tobe secured to a first vertebral body, wherein the assembly includes aframe made of a first material and at least one end plate made of asecond material different than the first material; a reducing plateconfigured to be slidably received over the central portion, wherein thereducing plate is configured to be secured to a second vertebral body;and an actuator configured to move the reducing plate relative to theframe.
 2. The vertebral implant of claim 1, wherein the assemblyincludes an enlarged head portion configured to receive a fastener forsecuring the assembly to the first vertebral body, and wherein a centralportion of the frame defines a lumen therein.
 3. The vertebral implantof claim 2, wherein the enlarged head portion is further configured toreceive a fastener restricting mechanism for limiting longitudinaltravel of the fastener.
 4. The vertebral implant of claim 3, wherein theassembly includes two enlarged head portions.
 5. The vertebral implantof claim 3, wherein the fastener restricting mechanism includes a screwhaving a head portion including a cutout therein.
 6. The vertebralimplant of claim 5, wherein the head portion of the screw includes aplurality of cutouts therein.
 7. The vertebral implant of claim 1,wherein the reducing plate is configured to be secured to the secondvertebral body by a plurality of fasteners.
 8. The vertebral implant ofclaim 7, wherein the reducing plate further includes at least onefastener restricting mechanism for limiting longitudinal travel of thefasteners.
 9. The vertebral implant of claim 8, wherein the at least onefastener restricting mechanism is configured to prevent unintentionalactuation of the actuator.
 10. The vertebral implant of claim 8, whereinthe reducing plate further includes a blocking plate for limitingrotation of the actuator.
 11. The vertebral implant of claim 1, whereinrotating the actuator in a first direction moves the reducing platetowards the frame.
 12. The vertebral implant of claim 1, wherein anexternal surface of the end plate includes at least one projection forgripping an adjacent bony surface.
 13. The vertebral implant of claim 7,wherein, when inserted into the second vertebral body, the plurality offasteners are disposed in a diverging relationship relative to oneanother.
 14. A vertebral implant, comprising: a frame assembly include aleft lateral portion, a central portion, and a right lateral portion,wherein the left and right lateral portions define enlarged headsconfigured to receive fasteners therein for securing the frame assemblyto a first vertebral body, and wherein the central portion defines alumen therethrough; a reducing member configured to be slidably receivedover the central portion, wherein the reducing member includes ananterior portion and a plurality of plates extending posteriorlytherefrom, wherein the plurality of plates define a channeltherebetween, wherein the channel is configured to receive a portion ofthe central portion; and an actuator configured to control a position ofthe reducing member relative to the frame assembly.
 15. The vertebralimplant of claim 14, further comprising a plurality of fastenerrestricting mechanisms for retaining the fasteners within the enlargedheads.
 16. The vertebral implant of claim 14, wherein a portion of theframe assembly includes a cover made of PEEK.
 17. The vertebral implantof claim 14, wherein the actuator is received in the reducing member andthe frame assembly.
 18. The vertebral implant of claim 17, wherein thereducing member is secured to a second vertebral body via a plurality offasteners.
 19. The vertebral implant of claim 18, further comprising afastener restricting mechanism for retaining the actuator and at leastone of the fasteners relative to the frame.
 20. A vertebral implant,comprising: a frame assembly having a left lateral portion, a centralportion, and a right lateral portion, wherein the left and right lateralportions define enlarged heads configured to receive fasteners thereinfor securing the frame assembly to a first vertebral body, and whereinthe central portion defines a lumen therethrough; a reducing memberconfigured to be slidably received over the central portion, wherein thereducing member includes an anterior portion and a plurality of platesextending posteriorly therefrom, wherein the plurality of plates definea channel therebetween, wherein the channel is configured to receive aportion of the central portion; and an actuator configured to control aposition of the reducing member relative to the frame assembly whereinthe plurality of plates are configured to expand as the reducing memberis actuated over the central portion of the frame assembly.